1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the same, and, in particular, to a semiconductor device having a non-volatile semiconductor memory device such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory and a method of manufacturing the same.
2. Description of the Background Art
A non-volatile semiconductor memory device having a floating gate electrode and a control gate electrode has conventionally been used. Generally, an insulating film is provided between the floating gate electrode and a silicon substrate.
Japanese Patent Laying-Open No. 7-249697 discloses such a non-volatile semiconductor memory device. In a semiconductor device described in Japanese Patent Laying-Open No. 7-249697, an insulating film between a floating gate electrode and a silicon substrate has a thickness increased at its end portion. The increase in the film thickness is due to formation of a bird's beak caused by thermal oxidization.